【Question】The issue of having to divide a distillation tower into sections due to its excessive height
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If the height of a distillation tower is too high, such as 150 meters, it needs to be divided into three sections. What impact would it have if there were no segmentation and it were just one single tower? Apart from the high construction costs and the swaying of the tower, are there any other drawbacks? For example, the heat load at the bottom of the tower increases, and the pressure difference rises. By high heat load and high pressure difference, I mean a comparison of an entire tower with three segmented towers. Thank you! !
Building the tower is also challenging; its height and weight place high demands on the cranes and the tower foundation.
There will be significant difficulties in equipment manufacturing, transportation, and installation; unless it is processed and manufactured on-site, the transportation issue cannot be resolved. Several cranes may be needed to work simultaneously during installation and lifting.
Transportation and lifting pose their own problems; safety during on-site construction is very important
The design of the tower itself and its foundation is complex, resulting in high manufacturing costs. Installation is also difficult, and it’s hard to maintain the tower’s verticality. Operating costs increase, as well as the requirements for auxiliary equipment; the head rating of the pumps also has to be increased. Maintenance of the equipment becomes more challenging. The costs of associated devices such as those used for backflow extraction also rise. The location of valves is often too high, making operation inconvenient. Factors such as the heat load at the bottom of the tower or pressure differences may have little impact
As for the tower itself, it is desirable that it be a single unit without any segments, as this is beneficial in terms of both manufacturing costs and safety. The challenge lies in how to install it – at 150 meters high, the difficulty and cost of lifting the entire structure in one go are extremely high; therefore, it is more practical to divide the tower into reasonable segments for construction purposes.
The 150m tower definitely needs to be welded on-site; heat treatment may also be required, making it a challenging task with difficult lifting operations； The tray efficiency should not be set too high. The heat load at the bottom of the tower and the total pressure drop across the tower need not increase much; theoretically, they should decrease rather than increase.
What you say makes sense. Our facility has two towers for propylene distillation; each tower is 55 meters high. The original design called for towers that were 110 meters tall, but installing them proved to be difficult, so they were changed to two separate towers
In actual production, towers that tall have never been seen; such heights pose difficulties in manufacturing, transportation, installation, operation, as well as maintenance.
I found a discussion about a 85-meter tower. I’m pasting the discussions from there. The web content isn’t blocked. Sharing what I found: loveliness: (1) If the condenser at the top of the entire tower is also placed near the ground, then the power requirement of the circulation pump remains the same; however, the power requirement of the vacuum pump is slightly higher in the case of a tower divided into sections； (2) If the top cooling is arranged at the top of the tower, the power requirement of the water circulation pumps in the segmented tower will be much lower; the power requirement of the vacuum pump will be slightly higher, but this can easily offset the increased power demand of the transfer pumps inside the tower ； The total power of the segmented tower will be slightly lower ； Regarding production costs: (1) The overall wall thickness of the tower is large; after segmentation, the wall thickness decreases significantly, which reduces equipment investment greatly. When this is taken into account in terms of depreciation, it represents a substantial amount, far exceeding the increase in energy consumption ； (2) The lifting is quite difficult, and the lifting costs will be much higher than those for towers with a lower height ； This part can also be allocated to depreciation ； Regarding the overall tower efficiency: (1) The impact of installation and manufacturing on tower efficiency (with other factors ignored) lies in the quality of tower manufacturing and installation, the quality of packing manufacturing and installation, as well as the quality of distributor installation and manufacturing. Moreover, the swaying of a fully assembled tower is greater than that of a segmented tower, and its straightness is more difficult to ensure ； So I think in terms of installation, segmented design should be better than a single tower ； (2) Operational impact: The entire tower is better, with fewer influencing factors ； The main difference between segmented operation and the conventional approach is the distribution in the gas phase and whether the material transfer rate remains stable. If automatic control is used, with the material transfer amount regulated by the liquid level, the actual impact on the tower is essentially the same as that in case of normal tower operation ； But the amount retained in the tower is slightly higher ； Therefore, I believe that although energy consumption may be higher, the overall manufacturing cost need not necessarily be high; on the contrary, once the tower reaches a certain height, constructing it in stages should result in lower production costs. (Information from the Internet): handshake. This post was last edited by Chuangxin Filler on 2009-3-11 at 17:04.]